Planning Assistance to States: Souris Basin Study

U.S. Army Corps of Engineers, St. Paul District
Published Sept. 25, 2017
Updated: March 29, 2022

Investigating and evaluating water supply and flood control options requires a thorough understanding of the water resources of the Souris Basin. This comprehensive study also updates the knowledge of the hydrological and hydraulic processes of the Souris River Basin under the current climate regime and climate change. Computer modeling is used to simulate various water supply and flood control options, and methods will be developed to evaluate the effects that these options will have on resource groups.


The study area includes the entire Souris River Basin to its confluence with the Assiniboine River and encompasses the key water control reservoirs: Rafferty, Grant Devine, Boundary and Lake Darling. The study is looking at the geographical limits of the basin in the provinces of Saskatchewan and Manitoba and the state of North Dakota.


Unprecedented flooding in the Souris River Basin in 2011 has focused attention on review of the water control operating plan during flood events. Interests in the basin, particularly in North Dakota, have asked that additional flood risk reduction measures be evaluated, above and beyond what is currently provided under the international agreement. The information gathered will help inform the state of North Dakota on their current flood risk and will be shared with international basin partners.


On September 8, 2017, a financial cost-share agreement was executed between the U.S. Army Corps of Engineers and the non-federal sponsor, the North Dakota State Water Commission.

The comprehensive work plan was sent to the International Joint Commission in October 2018. The study board updated the models and hydrographic curves, drafted a Plan of Study and will finalize the Plan of Study, completing the project in the spring of 2022.


Section 22 of the Water Resources Development Act of 1974 (Public Law 93‒251), as amended. The study is being conducted under the Corps’ Planning Assistance to States (PAS) program, following the 50/50 cost share formula with the non-federal sponsor. The sponsor may contribute additional funds beyond this formula.


The total study cost is $1,035,000 ($517,500 federal / $517,500 non-federal). The North Dakota State Water Commission is providing their cost share in $162,500 cash and $355,000 work-in-kind.